Analysis of Induction Mechanisms of an Insulin-Inducible Transcription Factor SHARP-2 Gene by (鈭?-Epigallocatechin-3-gallate
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- 作者：Ayumi Haneishi ; Katsuhiro Takagi ; Kosuke Asano ; Soichiro Nakamura ; Kazuya Yamada
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2012
- 出版时间：October 3, 2012
- 年：2012
- 卷：60
- 期：39
- 页码：9850-9855
- 全文大小：234K
- 年卷期：v.60,no.39(October 3, 2012)
- ISSN：1520-5118
文摘
The rat enhancer of split- and hairy-related protein-2 (SHARP-2) is an insulin-inducible transcription factor. In this study, we examined the mechanism(s) involved in the regulation of the rat SHARP-2 gene expression by (鈭?-epigallocatechin-3-gallate (EGCG). The induction of SHARP-2 mRNA by EGCG was repressed by pretreatments with inhibitors for either phosphoinositide 3-kinase (PI3K) or RNA polymerase II. Then, we examined a biological relationship between EGCG and transcription factor NF-魏B interfering with the insulin action. The protein levels of the NF-魏B were rapidly decreased by an EGCG treatment. Finally, the mechanism(s) of transcriptional activation of the rat SHARP-2 gene by both NF-魏B and EGCG was analyzed. While overexpression of the NF-魏B p65 protein decreased the promoter activity of the SHARP-2 gene, EGCG did not affect it. Thus, we conclude that EGCG induces the expression of the rat SHARP-2 gene via both the PI3K pathway and degradation of the NF-魏B p65 protein.